The subject matter described herein deals with measurement system component adjustment. Measurements systems in the context of this document include a component for obtaining measurements (referred to herein as a “sensor” or “probe”), where the component for obtaining measurements includes a replaceable sub-component or module (referred to throughout as a “sensor cap”), and a control component operatively connected to the component for obtaining measurements. The measurement system components may be provided as physically separate units or devices, or these units/devices may be integrated into a single unit that provides the appropriate functionality, as further described herein.
The sensor of a measurement system measures/monitors for various qualities in a given setting. A sensor may be sealed, such as for use in an aqueous environment, and measure/monitor characteristic(s) that may then be reported to a connected device (either a control component or other connected device(s)). For example, a luminescent dissolved oxygen (LDO) sensor is an optical sensor/probe that may be used to measure dissolved oxygen levels in an aqueous sample. An example of a dissolved oxygen sensor is the Advanced Hach LDO Process Dissolved Oxygen Probe, which is configured to continuously monitor dissolved oxygen in an aqueous sample using luminescent technology.
LDO sensors may be utilized for optical measurement of oxygen in several industrial applications, including but not limited to monitoring aquatic biology in waste water, blood gas analysis, fermentation control in biotechnology processes, wine microoxygenation, waste-water oxygen analysis, and industrial water applications. Optical measurement started with the measurement of relatively high oxygen levels, however now accurate measurement at levels below 1 μg·kg−1 are possible.
Operationally, LDO sensors may use a sensor cap portion that is coated with a luminescent material. The luminescent properties of the sensor cap are dependent on oxygen levels, forming the basis of operation. For example, in one example sensor, blue light from an LED illuminates a luminescent chemical in the luminescent material on the surface of the sensor cap. The luminescent chemical excites and then relaxes, releasing red light. The red light may be detected by a photodiode, with the time taken for the chemical to return to a relaxed state being measured. The red light that is given off by chemical is inversely proportional to the oxygen level of the sample. Thus, in higher oxygen environments, it takes a shorter amount of time for the luminescent material to return to a relaxed state. The oxygen concentration is thus inversely proportional to the time it takes for the luminescent material to return to a relaxed state.